The overall objective of this project is to evaluate the potential of hyperthermia combined with ionizing radiation for optimizing tumor control with minimal normal tissue response. Preclinical studies of response of spontaneously occurring canine tumors and normal tissues to hyperthermia and irradiation can provide valuable information leading to human clinical application. The canine tumors will include squamous cell carcinomas, fibrosarcomas and malignant melanomas. Serum proteins and isoenzymes will be measured electrophoretically before, during and following treatment to determine their relationship to extent of disease and response to therapy. Flow cytometry of tumor cells will be done to determine any relationship of tumor cell age distribution, growth function and DNA index to histologic characteristics of malignancy and to response to treatment. This information could aid in estimating which are the more sensitive human tumors and in the design of optimal treatment protocols of hyperthermia and irradiation.